Cutter bit and method of causing rotation thereof

ABSTRACT

A method and apparatus for turning a cutter bit in a continuous mining machine by providing one or more projections coupled to the bit having sufficient length so that when the cutter bit is in operation, material dislodged by the cutter bit, when falling, will impact the projections. The impact will generate a torque about the axis of the cutter bit causing the cutter bit to rotate a few degrees about the axis. Continual impact of the projections will provide continuous turning of the bit thereby increasing its useful life.

United States Patent [1 1 Radd [ 1 July 17, 1973 1 1 CUTTER BIT ANDMETHOD OF CAUSING ROTATION THEREOF [75] Inventor: Frederick J. Radd,Ponca City, Okla.

[73] Assignee: ContinentalOil Company, Ponca City, Okla.

[22] Filed: Dec. 31, 1970 [21] App1.No.: 103,211

[52] US. Cl. 299/10, 299/86 [51] Int. Cl. E2lc 35/18 [58] Field ofSearch 299/86, 91-93, 299/l0-l8;'175/354 [56] I References Cited UNITEDSTATES PATENTS 3,361,481 1/1968 Maddock 299/86 3,476,438 11/1969 Bower299/86 FOREIGN PATENTS OR APPLICATIONS France 299/86 PrimaryExaminer-Ernest R. Purser Attorney-Joseph C. Kotarski, Henry H. Huth,Robert B. Coleman, Jr., William J, Miller and David H. Hill [57]ABSTRACT A method and apparatus for turning a cutter bit in a continuousmining machine by providing one or more projections coupled'to the bithaving sufficient length so that when the cutter bit is in operation,material dislodged by the cutter bit, when falling, will impact theprojections. The impact will generate a torque about the axis of thecutter bit causing the cutter bit to rotate a few degrees about theaxis. Continual impact of the projections will provide continuousturning of the bit thereby increasing its useful life.

13 Claims, 14 Drawing Figures PAIENTEDJflL-l mm SHEEI 1 [if 3 INVENTOR.FREDERICK .1. R400 ATTORNEY PATENIEBMITW I 3.746.396

smears I ATTORNEY INVENTOR. FREDERICK J. 17400 BY Pmmwml v 145.396

SHkEI 3 0f 3' IN VENT OR.

FEEDER/0K J. R400 CUTTER BIT AND METHOD OF CAUSING ROTATION THEREOFBACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to improvements in the cutter bits used in continuous miningmachines. The invention relates particularly to a method for providingcontinuous turning of the cutter bit in order to even the wear of thecutter bit thereby prolonging its life.

2. Description of the Prior Art Many attempts have been made in the pastin an effort to solve the uneven wear of cutter bits used in continuousmining machines. These cutter bits' are mounted either in rotating drumsalong the periphery of the drum so that the axis of the bit is normal tothe axis of the drum, or on a series of parallel chain-type drives suchthat the axis of the bits is always normal to the surface of the chain.The continuous mining machines cause the bits to move into the materialbeing mined and tear away said material. If the bits are stationary onlyone surface will contact the material continuously. The single surfacewill wear excessively causing the bit to fail in a short period of timeby wearing away the metal supporting the hardened tungsten carbide tip.A typical cutter bit is disclosed in the US. Pat. to A. B. Bower, Jr.No. 3,476,438. This patent, along with the US. Pat. to J. K. Maddock No.3,361,481 and a French patent to Gerald Wayne Elders 1,483,463, areillustrative of patents relating to cutter bits used in continuousmining machines. These patents all are directed toward methods ofcontinuously rotating the bits by providing rib extensions along theouter conical surface of the bit so that friction of the rib against thematerial being cut will cause rotation of the bit.

SUMMARY OF THE INVENTION The present invention contemplates a method andapparatus for rotating a cutter bit not by the use of friction againstthe surface being cut, but rather by impact of the bit by fallingmaterial dislodged by the cutter bit.

In order to provide a means for rotating the bit by impact, novelprojections are mounted on the bit and extend radially from the bit. Theprojections are of sufficient length sothat material being dislodgedabove the bit will fall striking the projections. The forces thustransferred to the projections will cause a torque about the axis of thecutter bit imparting rotation thereto. Many types of configurations arepossible which will suffice to cause impact rotation of the cutter bit.The projections can be mounted directly to the bit by welding or keyedto the bit mechanically.

It is, therefore, an object of this invention to provide a method forrotating a cutting bit in an effort to extend the life of the bit.

It is a further object of thisinvention to use the forces generated byfalling mined material as a means of developing sufficient torque tocause continuous turning of a cutter bit in a mining machine therebyproviding even wear of the bit cutting surface resulting in an extendeduseful life of the cutter bit.

BRIEF DESCRIPTION OF THE FIGURES FIG. I is a side view of the cutter bitillustrating the preferred impact arms;

FIG. 2 is a front view of FIG. I; 7

FIG. 3 is a perspective view of FIGS. 1 and 2;

FIG. 4 illustrates the method of operation of the im' pact arms;

FIG. 5 is a modified impact arm mounting which is removable from thecutter bit, with the bit shown in dotted lines;

FIG. 6 is a cross-sectional view of the impact arm ring shown in FIG. 5;

FIG. 7 is a perspective view of a modified impact arm ring with thecutter position defined by dotted lines; and

FIGS. 8 through 14 illustrate various modifications of the impact ringshown in FIGS. 2 through 7.

SPECIFIC DESCRIPTION OF THE FIGURES Referring to all of the FIGURES, butin particular to FIGS. 1 through 4, a cutter bit generally referred toby the number 20 is shown. The cutter bit has a shank portion 21 and aconical cutting portion 22 axially formed with shank 21. A hardenedmaterial insert 23 is mounted in conical head 22 so that a portion ofinsert 23 projects from head 22. Insert 23 is generally made fromtungsten carbide-type materials, and is preformed to a sharpened pointto enhance the cutting of the bit.

A mounting for the cutter bit is generally referred to by number 24, andis shown in dotted lines since it forms no part of this invention, butis included to illustrate the method for holding the bit only. The bitnormally is anchored or secured in the mounting 24 by means of a pin 25;however, other means are also normally employed such as a ring having aplurality of dimples positioned to engage the holes for pins 25 in themounting. A circumferential groove 26 is formed behind the head 22, andis generally used to assist in removing the bit once it becomes worn.Ashoulder 27 attached to shoulder 27, and normal to thesurface of t theshoulder. The impact arms can be mounted by welding, brazing or anyother suitable means or forged directly during the manufacture of thecutterbit. lrnpact arms 30 can be made of any suitable material such asiron, steel, or other metals which can take an impact from fallingmaterial without breaking or bending severely. The length of the impactarms can vary greatly; however, the efficiency of the impact arms willincrease with their length. For example, referring to FIG. 2, the radiuslabeled R which is the distance between the axis of the shaft 21 and thetip of the impact arm can have a minimum just slightly larger than thediameter of the shoulder 27 and a maximum preferred length which doesnot exceed the diameter of the mounting 24.

The force generated (useful in rotating the shaft 21 is dependent on theweight of the material impacting arm 30 and the distance or radius Rwhere the impact occurred on arm 30. Thus, the longer the arm, thegreater the rotational force generated by the falling ma .terial. Themaximum length of arms 30, of course, de-

pends on the diameter of the rod forming the impact arms 30 and themechanical strength of the rod. Thus,

' if the rods were beyond the maximum diameter of mounting 24, the coalormined material could bend the rod back over mounting 24 causing thearms to jam thereby preventing rotation of the cutter bit.Furthercloseness of the adjacent cutter bits. The arms should notinterfere with the rotation movement of adjacent cutting bits. If arms30 are too short, the material will have little to impact, therebyreducing the chances of impact and, in addition, the radius R will beminimum, thereby generating the minimum force possible. The preferredembodiment uses arms which extend out to the diameter of mounting 24.

OPERATION The operation of the arms can be better understood byreferring to FIG. 4. A cutter bit 20 is moving in the direction of thearrow 32. As it moves, it breaks away material 33a, 33b or 336. Forexample, if 33b should impact arms 30a at point 34, a force will begenerated about the axis of cutter bit 20 in the direction of arrow 35.Mined material 330 will likely impact arms 300 since it is moving in thedirection of arrow 36. If material 33c impacts arms 300 a rotationalforce will be generated in the direction of arrow 35c. Mined material33a as it falls will probably impact arm 30a or one of the two arms 30bor 30d if these arms have moved into a position under material 33a. Fromthe description of the operation, it can be observed that the fallingmaterial will probably not cause a complete rotation of cutter 20, butwill cause a partial rotation. However, the random impact of the fallingmaterial on the impact arms will cause a continual rotation of bit 20',resulting in what amounts to a continuous rotation in both directions,clockwise and counterclockwise. The continual rotation will cause equalwear on all sides of the cutter bit cone 22 and equal wear on sharpenedhard insert 23. Since the softer metal on cone 22 will wear away first,insert 23 will always be exposed'as a cutting element. Since it isrotating, more or less, continuously (regardless of its direction), thepoint on insert 23 will remain fairly round. That is, it will notsharpen to a chisel shape which is likely if the bit ceases to rotate.

In an embodiment incorporating this invention which was successfullytested, a bit having a shaft diameter 21 of fifteen-sixteenths inch anda shoulder diameter 27 of 1 /4 inch had impact arms mounted on theshoulder comprising /4 inch diameter mild steel rods with a radius R of1% inch.

A second embodiment was successfully tested using the same rods 30 asabove and the same radius R with the rods mounted in the circumferentialgroove 26.

Av third embodiment was successfully tested where the rods 30 wereone-fourth inch in diameter, radius R was 1% inch and the rods were bentforward approximately 20 to increase the impact probability. From theabove tests, it was determined that bits without impact means averagedapproximately 64 hours of continuous use while bits with impact armsmade as described above operated I04 hours and were still useable.

MODIFIED IMPACT ARMS Referring to FIGS. and 6, a modified impact arm isillustrated and essentially comprises a disc 40 having an axial opening41 of a size sufficient to permit the disc to pass over the shank 21 ofcutter 20. A pair of notches 42 is formed in the opening 41 and engagesa raised portion 43 which cooperates with the notch 42 to preventturning of disc 40. A plurality of impact arms 44 are formed extendingfrom disc 40. The impact arms of this embodiment are bent at an angle 0in order to increase the probability of impact. Obviously, the

arms need not necessarily be bent. However, any configuration whichincreases the probability of impact is preferred over other embodiments.A notch 42 is illustrated in this embodiment. It is well within theskill of the art to incorporate any method which would prevent ring 40from turning on shaft 21. In fact, the ring could be welded to theshaft. The advantage of the embodiment shown in FIGS. 5 and 6, however,is that the ring can be used for a plurality of cutter bits insuccession; that is, once a bit becomes unserviceable, the ring can beremoved and placed on a new bit. The ring in this embodiment is shownmounted behind shoulder 27. It is obvious that the ring can be mountedover shoulder 27 or in the circumferential groove 26. Many ways can bedevised for attaching the ring to the cutter bit so that it can bereleased and reused and yet will not turn on shaft 21 once the cutterbit is put into service. Four impact arms are shown in the embodiment ofFIG. 6. It is obvious that many types of impact arms can be used andmore than four or less than four impact arms 44 can be incorporated. Ifless than four are used, effciency of the system may be impaired to someextent when compared to the performance of a cutter bit having fourimpact arms.

ADDITIONAL MODIFICATIONS The embodiments shown in FIGS. 7 through 14illustrate some of the ways the impact arms can be designed or formed inorder to accomplish the purposes of this invention. It should beunderstood that the embodiments illustrated in these FIGURES can eitherbe welded to the cutter bit or mounted releasably to the cutter bit asillustrated in FIGS. 5 and 6. FIGS. 7 and 8 illustrate impact arms whichhave notches 50 out about the periphery and extensions 51 which may bemounted to the arms 52, or formed with arms 52 by forging, turning,casting or other well-known manufacturing methods. The projections 51can also be formed by merely being bent up from the arms 52. The impactarms can then be attached to the cutter bit as previously described.

FIG. 8 illustrates that there can be at least two impact arms or fourimpact arms two being illustrated by dotted lines. The impact arms shownin FIGS. 9 and I0 are formed by merely dimpling or creasing a ring usinga hydraulic press or other well-known means. It is obvious, of course,the impact arms above-described can also be easily cast. The arms shownin FIG. 11 consist of a disc having a plurality of projections 61 aboutthe outer diameter of disc 60. The impact ring shown here can easily beformed by molding, forging, turning or any other well-known system.

The impact arms shown in FIG. 14 are similar to that shown in FIG. 11except the projections are radial and formed in the surface of a disc60. The impact arms shown in FIGS. 12 and 13 are obviously formed bycutting disc 60 and bending up radial portions to form impact arms. Itis obvious that many conceivable impact arms can be constructed whichoperate on the basic principle that falling material will cause arotational force to be applied to a cutter bit if the material strikes aprojection attached to the cutter bit. The main criteria for rotatingthe bit essentially consists in providing projections from the cutterbit surface having sufficient length not only to cause a sufficientrotating force being imparted to the cutter shaft when the arms areimpacted by falling material, but also having the arms sufficientlyplaced and oriented and in sufficient number so that there is a highlikelihood that falling material will strike the arms.

These and other features of this invention will become apparent whenreference is made to the drawings and the accompanying specification andclaims.

What l claim is:

1. ln a continuous mining machine, a method for turning a cutter bithaving a cylindrical shaft, a cutter head and one or more extendedprojections coupled thereto of a distance as measured from the axis ofsaid cutter bit at least twice the radius of said shaft, comprising,

a. passing said cutter bit through material to be mined, therebybreaking some of said material free above said cutter bit so that saidmaterial falls past said cutter bit;

b. placing said one or more extended projections under at least aportion of said falling material, whereby said falling materialimpacts'one or more of said projections causing said bit to turn.

2. In a cutter bit having a cylindrical shaft, a shoulder formed on oneend of said cylindrical shaft and a cutting head formed to saidshoulder, an improvement to said rotation of said cutter bit comprisinga plurality of spaced projections extending radially from said shoulderby a distance as measured from the axis of said cutter bit at leasttwice the radius of said shaft for imparting a rotational force aboutthe axis of said shaft by impact to said projections.

3. A device as described in claim 2, wherein said means coupled to thecutting head for imparting a rotation comprises a plurality of rodswelded to the cutting head and substantially radial to the axis of saidcutting head. i

4. A device as described in claim 2 wherein the length of said rodsradially extend from the cutting head on a radius of 1% inches from theaxis of said cutting head.

5. A device as described in claim 2 including a cutter bit holder havingan outer diameter, wherein said plurality of rods extends to the outerdiameter of said cutter bit holder. l

6. In combination with a cutter bit for a cutter bit holder said cutterbit having a shaft and a cutter head axially formed with the shaft, animprovement comprising means provided on said cutter bit and extendingnormal to said cutter bit by a distance as measured from the the axis ofsaid cutter bit greater than twice the radius of said shaft in a mannerto provide an impact surface whereby mined material when falling willimpact said impact surface causing rotation of said cutter bit.

7. A device as described in claim 6 wherein said means comprises aplurality of rods attached to the outer surface of said cutter bit andextending normal to the outer surface thereof.

8. An impact rotation means for a cutter bit comprising a disc having anexternal diameter greater than the external diameter of said cutter bit,and having an axial opening therethrough, means for coupling said cutterbit to said disc through said opening, and impact receiving means formedin said disc in a manner to project from the surface of said disc.

9. A device as described in claim 8, wherein said means for couplingsaid cutter bit to said disc through said opening comprises welding saiddisc around said opening to said cutter bit.

10. A device as described in claim 8, wherein said means for couplingsaid cutter bit to said disc through said opening comprises forming anengagingmeans in said opening and a mating engaging means on said cutterbit to prevent relative rotation of said cutter bit of said impactrotation means.

1l.'A device as described in claim 8, wherein said impact meanscomprises a plurality of raised portions on the surface of said disc.

12. A device as describedin claim 8 wherein said impact means comprisesforming a plurality of pairs of radial slots in said disc, and bendingthe portion of said disc between said pairs of slots at an angle withthe surface of said disc. 7

13. A device as described in claim 8 wherein said im pact meanscomprises forming a plurality of radial slots in said disc, and bendingportions of said disc adjacent said slot at an angle with said discsurface.

1. In a continuous mining machine, a method for turning a cutter bithaving a cylindrical shaft, a cutter head and one or more extendedprojections coupled thereto of a distance as measured from the axis ofsaid cutter bit at least twice the radius of said shaft, comprising, a.passing said cutter bit through material to be mined, thereby breakingsome of said material free above said cutter bit so that said materialfalls past said cutter bit; b. placing said one or more extendedprojections under at least a portion of said falling material, wherebysaid falling material impacts one or more of said projections causingsaid bit to turn.
 2. In a cutter bit having a cylindrical shaft, ashoulder formed on one end of said cylindrical shaft and a cutting headformed to said shoulder, an improvement to said rotation of said cutterbit comprising a plurality of spaced projections extending radially fromsaid shoulder by a distance as measured from the axis of said cutter bitat least twice the radius of said shaft for imparting a rotational forceabout the axis of said shaft by impact to said projections.
 3. A deviceas described in claim 2, wherein said means coupled to the cutting headfor imparting a rotation comprises a plurality of rods welded to thecutting head and substantially radial to the axis of said cutting head.4. A device as described in claim 2 wherein the length of said rodsradially extend from the cutting head on a radius of 1 1/2 inches fromthe axis of said cutting head.
 5. A device as described in claim 2including a cutter bit holder having an outer diameter, wherein saidplurality of rods extends to the outer diameter of said cutter bitholder.
 6. In combination with a cutter bit for a cutter bit holder saidcutter bit having a shaft and a cutter head axially formed with theshaft, an improvement comprising means provided on said cutter bit andextending normal to said cutter bit by a distance as measured from thethe axis of said cutter bit greater than twice the radius of said shaftin a manner to provide an impact surface whereby mined material whenfalling will impact said impact surface causing rotation of said cutterbit.
 7. A device as described in claim 6 wherein said means comprises aplurality of rods attached to the outer surface of said cutter bit andextending normal to the outer surface thereof.
 8. An impact rotationmeans for a cutter bit comprising a disc having an external diametergreater than the external diameter of said cutter bit, and having anaxial opening therethrough, means for coupling said cutter bit to saiddisc through said opening, and impact receiving means formed in saiddisc in a manner to project from the surface of said disc.
 9. A deviceas described in claim 8, wherein said means for coupling said cutter bitto said disc through said opening comprises welding said disc aroundsaid opening to said cutter bit.
 10. A device as described in claim 8,wherein said means for coupling said cutter bit to said disc throughsaid opening comprises forming an engaging means in said opening and amating engaging means on said cutter bit to prevent relative rotation ofsaid cutter bit of said impact rotation means.
 11. A device as describedin claim 8, wherein said impact means comprises a plurality of raisedportions on the surface of said disc.
 12. A device as described in claim8 wherein said impact means comprises forming a plurality of pairs ofradial slots in said disc, and bending the portion of said disc betweensaid pairs of slots at an angle with the surface of said disc.
 13. Adevice as described in claim 8 wherein said impact means comprisesforming a plurality of radial slots in said disc, and bending portionsof said disc adjacent said slot at an angle with said disc surface.